(i) Technical Field
The present invention relates to focal plane shutters and optical apparatus.
(ii) Related Art
Japanese Examined Utility Model Application Publication No. 06-024821 discloses a focal plane shutter provided with: a coil spring for movement to move blades; and a spring for fine adjustment to finely adjust the movement speed of the blades.
In Japanese Examined Utility Model Application Publication No. 06-024821, the biasing direction of the spring for fine adjustment is the same as that of the coil spring for movement. Thus, the blades are biased in the same direction by the two springs, so that the large impact is applied to the blades when the moving blades are stopped. For this reason, the blades might be damaged. In particular, the high shutter speed type of the focal plane shutter needs high-speed blades, so that the large impact might be applied to the blades when the blades are stopped. Thus, there is a large possibility that the impact might damage the blades.